Switching apparatus for electric shutter mechanisms

ABSTRACT

An electric shutter switching mechanism includes a first switch for selectively connecting a storage element with a light measuring circuit and a second switch for selectively connecting a timing circuit for closing the shutter with an electric power source. An operating member is movable between first and second positions which respectively represent the viewing condition and the photographing condition of the camera. The member interlocking with the operating member actuates the first switch to electrically isolate the storage element from the light measuring circuit and actuates the second switch to connect the timing circuit to the electric power source. With the operating member in the second position the interconnection between the members and the shutter releasing operation is terminated.

United States Patent [191 Kobori et al.

SWITCHING APPARATUS FOR ELECTRIC SHUTTER MECHANISMS Inventors: ToshioKobori; Masaru Ohba, both of Osaka, Japan Minolta Camera KabushikiKaisha, Osaka-shi, Osaka-fu, Japan Filed: Mar. 8, 1973 Appl. No.:339,282

Related US. Application Data Continuation-impart of Ser. No. 165,562,July 23, 1971, abandoned.

Assignee:

Foreign Application Priority Data July 25, 1970 Japan 45-65336 Nov. 27,1972 Japan 47-118107 References Cited UNITED STATES PATENTS 10/1969Nakamura 95/42 10/1970 Yanagi et al 95/42 X [451 Feb. 12, 1974 PrimaryExaminerSamuel S. Matthews Assistant Examiner-Michael L. GellnerAttorney, Agent, or Firm-Robert J. Lasker [57] ABSTRACT An electricshutter switching mechanism includes a first switch for selectivelyconnecting a storage element with a light measuring circuit and a secondswitch for selectively connecting a timing circuit for closing theshutter with an electric power source. An operating member is movablebetween first and second positions which respectively represent theviewing condition and the photographing condition of the camera. Themember interlocking with the operating member actuates the first switchto electrically isolate the storage element from the light measuringcircuit and actuates the secondswitch to connect the timing circuit tothe electric power source. With the operating member in the secondposition the interconnection between the members and the shutterreleasing operation is terminated.

12 Claims, 17 Drawing Figures PATENTEB FEB I 2 I974 3. 791 .277

sum 8 0r 9 1 SWITCHING APPARATUS FOR ELECTRIC SHUTTER MECHANISMS Thisapplication 'is a Continuation-in-Part of application Ser. No. 165,562,filed July 23, 1971, now abancloned.

BACKGROUND OF THE INVENTION The present invention relates tophotographic cameras provided with an electric shutter whichautomatically controls the exposure time by the photometric measurement(hereinafter referred to as the TTL type) of light rays passing throughan objective lens.

In a camera provided with an electric shutter of the TTL type whichautomatically controls the exposure time, it is difficult to conduct thephotometric measurement during exposure of the film. Therefore, thephotometric operation is carried out prior to the exposure and the lightmeasurement is stored and the exposure time control is carried intoeffect on the basis of the stored signal. It is well known that anelectric shutter provided with a photometric circuit, a storage circuit,and an exposure time control circuit may be used. A change-over switchis interposed between the photometric circuit and the storage circuit,and the operation of the change-over switch is carried out manually.Therefore, to obtain an accurate photometric operation, the time tooperate the change-over switch must be determined and its relationshipwith any other exposure motion such as the motion of a mirror in thecase of the single reflex camera. Consequently, the switching operationis not only troublesome, but also accompanied with variousinconveniences.

OBJECT OF THE INVENTION It is a primary object of the present inventionto provide a novel apparatus which eliminates such customary defects asdescribed above in a photographic camera provided with an electricshutter of the TTL type for automatically controlling exposure time.

It is another object of this invention to provide an apparatus in aphotographic camera provided with a TTL type electric shutter forautomatically controlling an exposure time, wherein a more precisephotometric measurement is carried out.

Another object of this invention is to provide an improved switchingapparatus interconnecting the photometric circuit and a storage circuitwhich is actuated by the pushing motion of the shutter release button.

It is still another object of this invention to provide an improvedswitching apparatus by means of which the switch between a photometriccircuit and a storage circuit is automatically retained in an openedposition until the shutter is allowed to begin its closing motion andfor automatically closing the switch in response to the closing motionof the shutter.

And yet another object of this invention is to provide a photographiccamera having an electric shutter provided with a variety of novelswitching mechanisms for connecting and disconnecting a photometriccircuit and a storage circuit.

SUMMARY OF THE INVENTION The present invention comprises a constructionin which a switch disposed between a photometric circuit and a storagecircuit in the TTL type automatic exposure control circuit comprisingthe photometric circuit,

the storage circuit and an exposure time control circuit, is opened bythe movement of either an operating lever or a locking lever which areboth. interlocked with the pressing motion of a release button.Subsequently, a preset lever is turned by means of the pressing motionof the release button via a locking lever, and amirror is actuated bymeans of the exposure motion, the shutter being accordingly opened andclosed in relation to the exposure time control circuit.

Moreover, the present invention is characterized in that it alsocomprises a construction in which the switch, disposed between thephotometric circuit and the storage circuit and having been opened bybeing interlocked with the pressing motion of the release button, isautomatically kept opened during the exposure motion. That is, this isachieved during the motion of the mirror and the opening and closingmotion of the shutter, on account of the movement of the preset lever,the special construction of the switch itself and a spacer interposedbetween the switch and the preset lever. Further, with the closingmotion of the shutter, the preset lever and the locking lever are bothreturned to their initial positions because of the movement of anarresting lever and a charging lever. The switch is thereafter closedautomatically.

The aforementioned construction is highly advantageous and usable withsuperior photographic techniques because with the first stage of thepressing motion of the release button the switch between the photometriccircuit and the storage circuit is opened, and with the second stage ofthe release pressing motion the exposure motion is activated. Thereby,the amount of light rays incident upon a light receptive element is notimpaired by such an affect due to the movement of the mirror that isgenerally seen in cameras, for example, of the single reflex type.Accordingly, the photometric value thereof obtained in a correctphotometric situation is capable of being accurately stored and byslightly pushing the release button the photometric data is firststored, and thereafter by further pushing the release button at a timeafter approaching nearer to or departing away from an object an actualexposure is capable of being carried into effect.

Moreover, with the construction according to the present invention, ifthe shutter releasing motion is once started, even though the releasebutton is thereafter freed, the switch between the photometric circuitand the storage circuit is kept opened until the shutter closing motionis terminated. Concurrently with the termination of the shutter closingmotion the switch between the photometric circuit and the storagecircuit is closed, thereby advantageously precluded is the necessity ofthe troublesome requirement that the release button must be kept pressedthroughout the duration of the exposure time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing anembodiment of an electrical circuit in accordance with the presentinvention;

FIG. 2 is a side elevation showing an embodiment including the mechanismfor operating a switch disposed between a photometric circuit and astorage circuit;

FIG. 3 and FIG. 4 are side elevations respectively showing differentoperating positions for the embodiment shown in FIG. 2;

FIG. 5 is a side elevation showing another embodiment including amechanism for operating a switch disposed between a photometric circuitand a storage circuit;

FIG. 6 is a side elevation showing a different operating position forthe embodimentshown in FIG. 5;

FIG. 7 is a side elevation showing still another embodiment including amechanism for operating a switch disposed between a photometric circuitand a storage circuit;

FIG. 8 and FIG. 9 are side elevations respectively showing differentoperating positions for the embodi ment shown in FIG. 7;

FIG. 10 is a side elevation showing yet another embodiment including amechanism for operating a switch disposed between a photometric circuitand a storage circuit;

FIG. 11 is a side elevational view of an operating component with theshutter cocked;

FIG. 12 is a bottom view of a body bracket portion of the embodimentof'FIG. 11;

FIG. 13 is a perspective view of the body bracket of FIG. l2;

FIG. 14 shows the position of the elements of FIG. 11 wherein theshutter button is shown at an initial first stroke; I

FIG. 15 shows the position of the elements of FIG. 11 wherein theshutter button is shown at its second stroke;

FIG. 16 shows the position of the elements of FIG. 11 wherein theshutter release button is maintained in the downwardly pressed positionafter the termination of exposure; and

rent of first compensating transistor T,-, flows through resistors R andR',. Additionally, the collector current is of a constant value,accordingly, a voltage of a definite value is applied to the seriesconnected photoconductive element R and resistor R,.

As described above, switch S, is interposed between photometric circuitA and memory circuit. B, and thisinvention is characterized in thetiming of the switching of switch S which is switched on and/or off inrelation to the pressing motion of the release button as furtherdescribed hereinafter.

Capacitor C, is charged to the voltage of junction a which is thephotometric result to be stored. The voltage of capacitor C, is appliedbetween the base and the emitter of transistor T Connected to thecollector of transistor T,- are delay capacitor C in the exposure timecontrol circuit C and timing switch 8., which is usually closed. Thejunction therebetween is wired to FIG. l7shows the position of theelements of FIG. 1 l

wherein the pressure on the shutter release button is removed prior tothe termination of exposure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagramshowing an electric shutter, wherein respectively denoted arephotometric circuit A, storage circuit B, exposure time control C, andmeter circuit D which indicates the exposure time. Power source E isconnected through power source switch S, to both resistors R and R toprovide proper voltages in photometric circuit A. Junction b betweendivider resistors R and R is connected to the base of first stagecompensating transistor T,,. Connected to the collector of transistor Tare series connected photoconductive element R and comparison resistorR,, and series connectedresistors R and R.,. The series connectedphotoconductive element R, and resistor R, and resistors R and R, are inparallel to each other and are connected to the collector of secondcompensating transistor T Resistor R, is interposed between the base andthe collector of transistor T of which the emitter is connected tovariable resistor R for representing the film sensitivity and theaperture stop value. The photometric output due to the photoconductiveelement R is obtained as a voltage at junction a between photoconductiveelement R and comparison I resistor R,. That voltage being applied viaswitch S to capacitor C, in memory circuit B.

In photometric circuit A, the respective resistance values ofphotoconductive element R and comparison resistor R, are much largerthan those of resistors R and R.,. Consequently, almost all of thecollector curthe base of transistor Tr, of a switching circuit.Electromagnet M for controlling the closing motion of the shutter isinterposed between the collector of transistor Tr, via anothertransistor Tr and the switching circuit. Main switch S of the exposuretime control circuit is arranged between the switching circuit and powersource E. Timing switch S.,, which is normally closed, and main switch8,, are both controlled by means of a member which is interlocked-withthe motion of the release button.

The output at junction a between photometric element R and comparisonresistor R, is applied to the base of amplifier Tr, in meter circuit Dwhich indicates the exposure time. The output of amplifier transistorTr, is further amplified by another amplifier transistor Tr of which theoutput is wired to ammeter Am.

In the circuit constructed as described above, when power source switchS, is closed, indicated on ammeter Am is the shutter speed whichcorresponds to the potential at junction a, and which is responsive tothe aperture stop value and the film sensitivity having beenrespectively set therein. Also, memory capacitor C, is connected tojunction a so that the logarithmically compressed voltage which isproportional to the logarithmic value of the brightness of an object isstored by capacitor C,.

Thereupon, switch S is first opened by being interlocked with theshutter releasing operation, photometric circuit A and storage circuit Bare thereby isolated from each other. Main switch S is next closed incompliance with a motion interlocked to the subsequent releasingoperation. Timing switch S is opened simulta neously with the startingtime of the shutter opening motion so that the charging of delaycapacitor C is thereby started, and when its charging voltage reaches adefinite value, the switching circuit is reversed so as to actuateelectromagnet M, the shutter closing motion being accordingly carriedinto effect.

FIG. 2 illustrates an embodiment of the mechanical part of a cameraindicating a mechanism for activating an electric shutter thereof,wherein, a photographic lens not shown in the drawing is located at theright side of optical axis X. The light rays transmitted through thephotographic lens is reflected by mirror 5 and reaches finder eye piece13 via pentaprism 12. Two photoconductive elements R shown in FIG. 1 aremounted on pentaprism l2, and the average brightness of an object imageon focussing screen 11 is photometrically measuredby means ofphotoconductive elements R Numeral 1 denotes an operating lever which isoperated by being interlocked with a release button not shown in thedrawing, and operating lever 1 moves upward in response to the pressingmotion of the release button.

Locking lever 2 is counterclockwise biased about its pivot 2b due to aspring not shown, an arm thereof is so disposed as to be engageable withprojection Ila at the lowest end of operating lever 1, locking portion2d erected at the other end thereof locks first arm 3d of preset lever3. Protruding' pin 2a is also formed on locking lever 2, and when therelease button has not yet been pressed down as shown by the situationin FIG. 2, pin 2a is located at the position where switch S disposedbetween photometric circuit A and storage circuit B has been therebyclosed as shown in FIG. I.

Preset lever 3 is biased to spring 4 so as to be turned clockwise, andspring 4 is bridged between second arm 3e and charging lever 8.

Preset lever 3 is further provided with third arm 3a which moves mirror5 when preset lever 3 is turned clockwise, and with fourth lever 3bwhich pushes shutter release member 6 when it is in the position wheremirror 5 has been moved. Numeral 7 denotes an arresting lever which isturned clockwise about pivot 7a when the shutter is closed. Arrestingpawl 7b of arresting lever 7 is engaged with end portion 8a of charginglever 8 so as to check the counterclockwise turning of charging lever 8by spring 9 which is bridged between charge lever 8 and the camera body.

In the construction of FIG. 2 as described above, when the releasebutton is pressed down, operating lever I is displaced upward. Arm 2c oflocking lever 2 is thereby pulled up by projection in at the lowest endof operating lever 1, locking lever 2 being accordingly turnedclockwise. On account of the turning of locking lever 2, switch S whichhas been kept closed by pin 2a of locking lever 2 is first opened, andafter it is com pletely opened, the engagement between locking por-'tion 2d and first arm 3d is disengaged. Consequently, preset lever 3 isturned clockwise due to spring 4 so that its third arm provided thereonfor turning mirror 5 pushes up pin 5a which is fixed to one side ofmirror 5, the mirror being thereby rapidly moved upward so as to beturned about its pivot 5b. Since preset lever 3 continues to rotateclockwise even after mirror 5 has been moved, shutter release member 6is pushed by fourth arm 3b so that the shutter starts its openingmotion.

Concurrently with the starting of the shutter opening motion, mainswitch 5;, shown in FIG. 1 is closed and timing switch S similarly shownin FIG. I is opened. The situation at this moment is shown in FIG. 3,and as is clearly apparent, the extreme end of first arm 3d of presetlever 3 which has been turned clockwise comes into contact with sideface 2e of locking lever 2. Thereby locking lever 2 has been restrainedat the position where switch S has been, kept opened. This situationsuggests that, if an exposure is once started by fully pressing down therelease button, eventhough the release button is thereafter left free soas to have operating lever l returned downwardly while the exposure isstill in progress, switch S will be restrained by locking lever 2 so asto continuously remain in its opened position.

When the shutter is closed after a definite'time due to the operation ofexposure time control circuit C Shown in FIG. I, arresting lever 7 isturned clockwise about its pivot 7a by being interlocked with amechanism not shown in this drawing. Accordingly, cocking lever 8 isturned counterclockwise about spindle 812 by the bias of spring 9. Therotated cocking lever 8 comes into contact with projecting pin 30erected on second arm 3e of preset lever 3 and pushes projecting pin 30owing to the tractive force of spring 4. Thereby preset lever 3 isreturned as shown in FIG. 4 to its initial location shown in FIG. 2.Concurrently therewith, mirror 5 and locking lever 2 are also returnedto their respective initial locations and switch S is accordinglyclosed.

When the shutter is cocked, cocking lever 8 is turned clockwise until itcomes into engagement with arresting pawl 71;,- thereby both springs 9and 4 are tensioned to restore the initial situation shown in FIG. 2.

FIG. 5 shows another embodiment of the mechanical part of a camera foractuating an electric shutter thereof, and FIG. 6 shows a differentoperating position therein, wherein the location at which switch S isactuated is different from that of the embodiment shown in FIG. 2.

That is, operating lever 1 is provided on its upper portion withprotrusion llb for opening switch S and preset lever 3 is provided onits first arm 3d with pin 3f for pushing up lower contact of switch 8;.

In the construction as described above, when operating lever 1 is movedupward, similar to the case of FIG. 2, by being interlocked with thepressing down motion of the release button, an upper contact of switch Sis first pushed up by projection 1b of operating lever I, so that switchS is opened. Because of the subsequent upward movement of operatinglever I, the engagement between locking lever 2 and preset lever 3 isdisengaged by protruded portion Ia at the lowest end thereof. Therebymirror 5 is quickly moved similar to the first embodiment. In this case,because of the clockwise turning of first arm 3d of preset lever 3, pin3fis retracted from the lower contact which has an inherent tendency todepart from the upper contact of switch S Accordingly, the lower contactof switch S is completely released and thereby capable of naturallybending downward so as to be spaced apart from the upper contact pieceto such an extent that, even if the upper contact moves down by beingreleased due to projection lb of operating lever 1, switch S is capableof being accordingly held in its opened condition.

The returning operation is similar to that of the first embodiment,wherein, when the shutter is closed, preset lever 3 is returned from theposition in FIG. 6 to the position in FIG. 5, and when mirror 5 is alsoreturned to its initial location, switch S is thereby closed.

FIG. 7 shows the third embodiment of the mechanical part of a camera foractivating the electric shutter thereof, and FIG. 8 and FIG. 9 showrespectively different operating positions thereof. The construction ofswitch S of this embodiment is also different from those of the firstand the second embodiments described hereinabove.

Switch S consists of slide conatact 14a which is fixed to operatinglever 1 and brushlS which is fixed to first arm 3d of preset lever 3.When the release button is pressed down, in compliance with the upwardmovement of operating lever 1, locking lever 2 is rotated clockwise,resulting in the disengagement of locking lever 2 from first arm 3d ofpreset lever 3. Consequently, first arm 3d is slightly lowered, so thatbrush 15 is, before mirror is moved up, passed across the lower edge ofslide contact 14a, switch S is thereby opened. (This situation is shownin FIG. 8). In the situation shown in FIG. 9 in which mirror 5 has beenalready moved up, brush is turned clockwise in company with preset lever3 so as to be spaced far apart from the lower edge of slide contact 14ato such an extent that even if the release button is let free so thatoperating lever l is returned to its initial position, so long as theshutter is not closed and thereby preset lever 3 and mirror 5 are bothreturned to their respective initial positions, switch S is neverclosed. 14b denotes an insulating material adhered to operating lever 1.

FIG. 10 shows the fourth embodiment of the mechanism for controllingswitch S between the photometric circuit and the storage circuit in theelectric shutter. In this embodiment, switch opening lever 16 isinterposed between switch S and operating lever 1, and a spacer 17 isdisposed between switch opening lever 16 and first arm 3d of presetlever 3. Accordingly, because of the pressing down motion of the releasebutton, operating lever 1 is moved upward, the right end of switchopening lever 16 is thereby pushed up by upper end 1c of operating lever1, so that switch opening lever 16 is turned counterclockwise about itspivot 16a. Projecting pin 16b provided on switch opening lever 16 actson switch S and switch S is thereby opened.

Because of the subsequent upward motion of operating lever 1, first arm3d of preset lever 3 is disengaged from locking lever 2 asaforementioned, preset lever 3 is thereby turned clockwise so that themirror not shown herein is quickly moved up similarly to the embodimentsdescribed hereinbefore. Concurrently, spacer 17 is turned clockwiseabout its axis 17a by means of any suitable biasing force such as aspring or the like, until it is located at the position shown by adotted line. By virtue of spacer 17 located between first arm 3d ofpreset lever 3 and switch opening lever 16, even though the operatinglever has been returned to its initial location, switch S is capable ofbeing held in its opened condition.

And switch S is closed when the shutter is closed and thereby presetlever 3 is returned to its initial location similar to the embodimentsdescribed hereinabove.

In the embodiments previously described, main switch S is controlled inassociation with the operation of the release button, while theoperation of storage switch S is controlled by actuating lever 1 or locklever 2. In such embodiments, if the release button is maintained in thedownwardly pressed position after the termination of exposure, mainswitch S is maintained in' the closed position, whereby exposure timecontrol circuit C remains in the operative condition, which results inthe unnecessary consumption of the power source dry cells.

In contradistinction thereto, the construction of the embodiment asshown in FIGS. 11 through 17 is such that a switch lever is actuated bythe release operation and maintained in the operative condition from thecommencement of exposure until the termination thereof. Upon thetermination of exposure, the switch lever is released. The switch lever,only when in the operative situation, opens storage switch S to closemain switch S By controlling the operation of main switch 5;, by meansof the switch lever, the unnecessary flow of current to exposure controlcircuit C is prevented,

and the actuation of storage switch S is ensured to a greater extent.

Throughout FIGS. 11 to 17, actuating lever l is journaled by axle 1c andis urged in the clockwise direction by spring 16. Actuating lever 1 isinterconnected, by link member 17, with release button 18, so that whenrelease button 18 is pushed downwardly, actuating lever 1 is rotated inthe anti-clockwise direction against the force of the spring 16 topositions as shown in FIGS. 14 and 15. Link lever. 19 is journaled byaxle 1d on actuating lever 1 and has a bias to be rotated in theanticlockwise direction by feeble spring 19a. Link lever 19 is providedwith a projection 19b facing axle 1d and end face formed with releaseprojection 19d extending in a direction opposite to projection 19b.

Formed on the camera body is body bracket 20, on which control lever 22is journaled by axle 21, as best seen in FIG. 12. Control lever 22 hasarm 22:: connected with the other end of spring 16, whereby controllever 22 is urged in the clockwise direction. Control lever 22 has aportion consisting of bottom apex end 22a, engaging stepped portion 22band bottom base end 220 and is formed with bent projection 22d engagingwith or disengaging from projection 1911.

Further, detention lever 23 is journaled by axle 23a on bracket 20 andengages pin 24d attached to first arm 240 of switch lever 24, which isrotatably journaled by axle 24a on the camera body and rotated in theclockwise direction by spring 24b. Switch lever 24 has second arm 24cprovided with pin 24f. Pin 24f is engageable with either of the movablecontacts of storage switch S or main switch S When switch lever 24 ispositioned for rotation in the anti-clockwise direction against theforce of spring 24b, as shown in FIG. 11, pin 24f closes storage switchS while maintaining main switch S in the opened position. And as soon asrelease button 18 is pressed downwardly, switch lever 24 is rotated inthe clockwise direction by the action of spring 24b at the initial firststroke of the release button by a mechanism to be described later. Thus,pin 24f releases storage switch S while closing main switch 8;; as seenin FIG. 14. Third arm 24g of switch lever 24, when actuating lever 1 isin the position for rotation in the clockwise direction as shown in FIG.11, engages engaging arm le of the actuating lever, hence switch lever24 rotates in the anti-clockwise direction against the force of spring24b.

Formed at both sides of body bracket 20 are bearing holes 20a and 20breceiving therein lock lever 25. Lock lever 25 is urged leftwardly bybiased spring 25b connected between plate 25a rigid with the left end oflever 25 and bracket 20a. Block 26 is rigidly attached to lock lever 25so as to be moved therewith and has upwardly extending arm 2611 providedwith actuating pin 26b.and ro'd 26c projecting frontwardly as seen inFIG. 11 and slot 26d extending at a right angle with respect to the axisof rod 260. Slot 26d receives therein bottom edges 22a and 220 of thecontrol lever in a manner of allowing a sliding motion of the bottomedges. Further, rod 26c extends forwardly to slidingly fit its forwardend in aperture 200 formed on a front wall of bracket 20.

Mirror lever 27 having first arm 27b provided with forked portion 270receiving therein actuating pin 26b is rotatably journaled by axle 27aon the camera body. Second arm 27a of mirror lever 27 has pin 27e whichengages movable mirror 5 rotatably journaled by axle a on the camerabody and having a tendency to be rotated in the clockwise direction byspring 5b. Third arm 27f thereof is projected so as to actuate adiaphragm mechanism (not shown).

A shutter closing member, for example, cam plate 28 mounted rigidly withaxle 28a rotates after the completion of travel of a focal plane shutterand is engageable with end plate 25a of lock lever 25. 25 is a shutterrelease member operated by movable mirror 5.

The device having a construction as described above operates as follows.In the position as shwon in FIG. 11 where the shutter has been cocked,lock lever 25 is shown in the rightwardly moved position with spring 25bcompressed, wherein pin 260 is locked by engagement with stepped portion22b of control lever 22. Switch lever 24, of which third arm 24g is inengagement with arm le of actuating lever 1 which has been rotated inthe clockwise direction by spring 16, takes a position for rotation inthe anti-clockwise direction against the force of spring 24b. Pin 24f ofsecond arm 24e closes storage switch S while maintaining main switch Sin the opened position. Bottom apex end 22a of control lever 22, whichhas been rotated in the clockwise direction, urges pin 24d of first arm24c of switch lever 24 in the clockwise direction by way of detentionlever 23, thereby arresting switch lever 24 at the position for rotationin the anticlockwise direction.

As the device is maintained in the position described, release button 18is pressed downwardly as shown in FIG. 14. Actuating lever l, at theinitial first stroke of the release button, is caused to rotate by linkmember 17 in tne anti-clockwise direction by a given angle, whereuponengaging arm 1e thereof becomes disengaged from third arm 24g of switchlever 24. At this time, control lever 22 in position for clockwisedirectional rotation still acts on switch lever 24 by detention lever 23so as to control the clockwise rotation of lever 24. With the upwardmovement of link lever 19 caused by the anti-clockwise directionalrotation of actuating lever 1, projection 19!) thereof is brought intoengagement with projection 22d of control lever 22, to thereby causelever 22 to rotate in the anti-clockwise direction against the force ofspring 16. Consequently, detention lever 23 is permitted to rotate inthe clockwise direction and switch lever 24 is also caused to rotate inthe clockwise direction by spring 24b. Thus, pin 24f becomes disengagedfrom storage switch S to thereby open it, while in turn the pin closesmain switch S Because of that movement, the output voltage in the lightmeasuring circuit, just before storage switch S is opened, will bestored instorage capacitor C1 and exposure time control circuit C isrendered operative.

As for lock lever 25 at this stage, the engagement of stopped portion2212 with slot 26 is still maintained; hence the leftward slidingmovement of lock lever 25 by spring 25b is not yet caused.

At the subsequent second stroke where release button 18 is furtherpressed downwardly, the rotation of actuating lever I in theanti-clockwise direction causes control lever 22 to rotate in theanti-clockwise direction by link lever 19. Thereby, stepped portion 22bof the control lever becomes disengaged from slot 26d, thereby causinglock lever 25 to move leftwardly together with block 26, by the actionof spring 25b. Thus, actuating pin 26b in engagement with forked portion27c rotates mirror lever 27 in the clockwise direction so that pin 27ccauses movable mirror 5 to rotate,

re against the force of spring 5b, in the anti-clockwise direction fromthe viewing position to the photographing position. Third arm27f'adjuststhe diaphragm to a given aperture setting. Mirror 5, byrotation of the photographing position, becomes engaged with shutterrelease member 29 to actuate it, thereby initiating theexposure, whiletrigger switch S is released to effect the charging of capacitor C Whenpin 26: reaches the left side end of aperture 20c and is brought intoabutment with release projection 19d link lever 19 is caused to rotatein the clockwise direction against the force of spring 19a to therebydisengage engaging projection 19b from projection 22d of control lever22. This causes the rotation of control lever 22 in the clockwisedirection by the action of spring I6, and the clockwise directionalrotation of control lever 22 is stopped when bottom base end 220 engagesin slot 26d. Because of this engagement, the operation of bottom apexend 22a is controlled, hence the rotation of switch lever 24 in theanti-clockwise direction by detention lever 23 is not yet initiated.Accordingly, storage switch S is maintained in the opened position whilemain switch S is maintained closed. At this stage, end face 19c rests onpin 26c, hence the return motion of actuating lever I in the clockwisedirection is not yet caused.

When the voltage of capacitor C of the electric control circuit Creaches a given level, the switch circuit is cut off to thereby renderelectromagnet Mg nonconductive, and the shutter charging member isactuated. Upon the termination of exposure, cam plate 28 is rotated to aposition where projected face 285 thereof urges end plate 25arightwardly against the force of spring 25b, as shown in FIG. 16,whereby pin 26b causes mirror lever 27 to rotate in the anti-clockwisedirection. Thus, movable mirror 5 is allowed to rotate in the clockwisedirection by spring 5b into the viewing position. During this movement,bottom apex end 22a is caused to engage in slot 26d by stepped portion22b. This causes, by means of detention lever 23, the rotation of switchlever 24 in the anti-clockwise direction, and consequently pin 24freleases main switch S while in turn closing storage switch SAccordingly, in case the object to be photographed is bright, hence thetime of exposure is short, and if release button 18 is maintained in thedownwardly pressed position as shown in FIG. 16, switch lever 24 isallowed to rotate in the anti-clockwise direction by detention lever 23by means of control lever 22 so as to turn main switch S to the openedposition. Thereby, exposure time control circuit C is renderedinoperative to prevent unnecessary current flow to that circuit.

In case the object to be photographed is dark and the time of exposureis relatively long, even after the pres sure exerted on release button18 is removed prior to the termination of exposure as shown in FIG. 17,pin 26b still retains the movable mirror in the photographing positionby means of mirror lever 27 and lock lever 25 which has been slid to theleftward position at this stage. Furthermore, pin 260 is in engagementwith forward end l9c to arrest the movement of lever 19 and bottom baseend 220 is in engagement with slot 26d. Hence the rotation of switchlever 24 in the anticlockwise direction is prevented. Thus, main switchS is maintained in the closed condition, such that exposure time controlcircuit C remains operative until the exposure is terminated.

What is claimed is:

1. In a single lens reflex camera operable in a viewing condition and aphotographing condition and comprising a light measuring circuit havinga light receptive element for receiving light from an object to bephotographed through an objective lens and for generating an outputvoltage representative of the object light intensity, means for storingsaid output voltage, and means for timing the closing of a shutter inaccordance with said stored voltage, anda switch mechanism including afirst switch for selectively connecting said means for storing and saidlight measuring circuit and a second switch for selectively connectingsaid means for timing the closing of the shutter and an electric powersource, comprising:

an operating member movable between a first position and a secondposition respectively representing said viewing condition and saidphotographing condition;

an interlocking member interlocking with said operating member andmovable between a first position for restraining said operating memberin said first position and a second position for allowing said operatingmember to move to said second position thereof and being retained insaid second position when said operating member is located in saidsecond position thereof;

means responsive to shutter releasing operation to move from a firstposition thereof to a second position thereof; means for interconnectingsaid means responsive to shutter release operation with saidinterlocking member for moving the latter from said first position tosaid second position thereof with the movement of the former from saidfirst position to said second position thereof; means for actuating saidfirst switch to electrically isolate said means for storing from saidlight measuring circuit and said second switch to electricallyconnect'said means for timing the closing of said shutter to saidelectric power source with said interlocking member moving from saidfirst position to said second position thereof; means for releasing theinterconnection between said means responsive to shutter releasingoperation and said interlocking member when said operating member islocated in said second position; and

means for positioning said operating member in said first position inresponse to the termination of exposure.

2. A single lens reflex camera as in claim 1, wherein said first switchconnects said means for storing to said .light measuring circuit andsaid second switch isolates said means for timing the closing of theshutter from said electric power source when said interlocking member islocated in said first position thereof.

3. A single lens reflex camera as in claim 1, wherein said operatingmember includes a rod slidable relative to the camera body from a firstposition to a second position and is biased to said second position by aspring, a cam plate rotatable together with a member for terminatingexposure, and a member for engaging with said cam plate.

4. A single lens reflex camera as in claim 3, wherein said rod includesa projection having a slot, said interlocking member is composed of alever supported rotatably by a pin on the camera body and provided withfirst and second edges for engaging with said slot through a step forrestraining said operating member in said first position thereof, andsaid interlocking member is positioned in said first position thereofwhen said first edge engages with said slot and positioned in saidsecond position thereof when said second edge engages with said slot.

5. A single lens reflex camera as in claim 1, wherein said means fortiming the closing of a shutter in accordance with said stored voltageincludes a switching circuit and electromagnetic means for triggering aclosing member of the shutter to terminate exposure in response to theactuation of said switching circuit, and said second switch isolatessaid electromagnetic means from said electric power source with themovement of said interlocking member from said second position to saidfirst position thereof.

6. In a single lens reflex camera operable in aviewing condition and aphotographing condition and comprising a light measuring circuit havinga light receptive element for receiving light from an object to bephotographed through an objective lens and for generating an outputvoltage representative of the object light intensity, means for storingsaid output voltage, and means for timing the closing of a shutter inaccordance with said stored voltage, and a switch mechanism including aswitch for selectively connecting said means for storing and said lightmeasuring circuit, comprising:

an operating member movable between a first position and a secondposition respectively representing said viewing condition and saidphotographing position;

means for retaining said operating member in said first position; meansmovable from a first position to a second position for releasing theretainment of said operating member in response to shutter releasingoperation;

means following said movable means for actuating said switch toelectrically isolate said means for storing from said light measuringcircuit with said movable means moving from said first position to saidsecond position;

said means for retaining said movable means and said following meansactuating said switch prior to the releasing of said operating member;and

means for restraining said following means in the position for actuatingsaid switch.

7. A single lens reflex camera as in claim 6, wherein said followingmeans is interconnected with said means for retaining to move therewith,and said means for retaining is movable between a first position forretaining said operating member in said first position thereof and asecond position for allowing said operating member to move to saidsecond position and is interlocked with said movable means to movetherewith when the latter moves from the first position to the secondposition thereof, and further comprising means for restraining saidmeans for retaining in said second position thereof with said operatingmember in said second position thereof, and means for disconnecting saidmeans for retaining from said following means so that said means forretaining may return regardless of said movable means when saidoperating member returns from said second position thereof.

8. A single lens reflex camera as in claim 6, further comprising meansfor preventing said movable means from returning to said first positionthereof when said operating member is in said first position thereof.

9. A single lens reflex camera as in claim 8, wherein said means forretaining retains said operating member in their respective firstpositions and vice versa in their respective second positions, and theoperating member includes said means for disconnecting said means forretaining from said following means.

10. In a single lens reflex camera operable in a viewing condition and aphotographing condition and comprising a light measuring circuit havinga light receptive element for receiving light from an object to bephotographed through an objective lens and for generating an outputvoltage representative of the object light intensity, means for storingsaid output voltage, and means for timing the closing of a shutter inaccordance with said stored voltage, and a switch mechanism including aswitch for selectively connecting said means for storing and said lightmeasuring circuit, comprising:

an operating member movable between a first position and a secondposition respectively representing said viewing condition and saidphotographing position;

means movable between a first position for retaining said operatingmember in said first position and a second position for allowing saidoperating member to move to said second position;

means responsive to shutter releasing operation to bring said movablemeans from said first to said second position thereof to release theretainment of said operating member;

means for restraining said movable means in said second position thereofwith said operating member in said second position thereof;

means for releasing said means for restraining with said operatingmember returning from said second position; means for disconnecting saidmovable means from said responsive means so that said movable means mayreturn regardless of said responsive means when said operating memberreturns from said second position thereof; and

means for actuating said switch to electrically isolate said means forstoring from said light measuring circuit with said movable means movingfrom said first position to said second position, said movable means andsaid means for actuating operating said switch prior to the releasing ofsaid operating member.

11. A single lens reflex camera as in claim 10, wherein said means foractuating said switch is a member interlocked with said movable means tomove therewith.

12. A single lens reflex camera as in claim 11, wherein said movablemeans retains said operating member in their respective first positionsand vice versa in their respective second positions, and said operatingmember includes said means for disconnecting said movable means fromsaid responsive means

1. In a single lens reflex camera operable in a viewing condition and aphotographing condition and comprising a light measuring circuit havinga light receptive element for receiving light from an object to bephotographed through an objective lens and for generating an outputvoltage representative of the object light intensity, means for storingsaid output voltage, and means for timing the closing of a shutter inaccordance with said stored voltage, and a switch mechanism including afirst switch for selectively connecting said means for storing and saidlight measuring circuit and a second switch for selectively connectingsaid means for timing the closing of the shutter and an electric powersource, comprising: an operating member movable between a first positionand a second position respectively representing said viewing conditionand said photographing condition; an interlocking member interlockingwith said operating member and movable between a first position forrestraining said operating member in said first position and a secondposition for allowing said operating member to move to said secondposition thereof and being retained in said second position when saidoperating member is located in said second position thereof; meansresponsive to shutter releasing operation to move from a first positionthereof to a second position thereof; means for interconnecting saidmeans responsive to shutter release operation with said interlockingmember for moving the latter from said first position to said secondposition thereof with the movement of the former from said firstposition to said second position thereof; means for actuating said firstswitch to electrically isolate said means for storing from said lightmeasuring circuit and said second switch to electrically connect saidmeans for timing the closing of said shutter to said electric powersource with said interlocking member moving from said first position tosaid second position thereof; means for releasing the interconnectionbetween said means responsive to shutter releasing operation and saidinterlocking member when said operating member is located in said secondposition; and means for pOsitioning said operating member in said firstposition in response to the termination of exposure.
 2. A single lensreflex camera as in claim 1, wherein said first switch connects saidmeans for storing to said light measuring circuit and said second switchisolates said means for timing the closing of the shutter from saidelectric power source when said interlocking member is located in saidfirst position thereof.
 3. A single lens reflex camera as in claim 1,wherein said operating member includes a rod slidable relative to thecamera body from a first position to a second position and is biased tosaid second position by a spring, a cam plate rotatable together with amember for terminating exposure, and a member for engaging with said camplate.
 4. A single lens reflex camera as in claim 3, wherein said rodincludes a projection having a slot, said interlocking member iscomposed of a lever supported rotatably by a pin on the camera body andprovided with first and second edges for engaging with said slot througha step for restraining said operating member in said first positionthereof, and said interlocking member is positioned in said firstposition thereof when said first edge engages with said slot andpositioned in said second position thereof when said second edge engageswith said slot.
 5. A single lens reflex camera as in claim 1, whereinsaid means for timing the closing of a shutter in accordance with saidstored voltage includes a switching circuit and electromagnetic meansfor triggering a closing member of the shutter to terminate exposure inresponse to the actuation of said switching circuit, and said secondswitch isolates said electromagnetic means from said electric powersource with the movement of said interlocking member from said secondposition to said first position thereof.
 6. In a single lens reflexcamera operable in a viewing condition and a photographing condition andcomprising a light measuring circuit having a light receptive elementfor receiving light from an object to be photographed through anobjective lens and for generating an output voltage representative ofthe object light intensity, means for storing said output voltage, andmeans for timing the closing of a shutter in accordance with said storedvoltage, and a switch mechanism including a switch for selectivelyconnecting said means for storing and said light measuring circuit,comprising: an operating member movable between a first position and asecond position respectively representing said viewing condition andsaid photographing position; means for retaining said operating memberin said first position; means movable from a first position to a secondposition for releasing the retainment of said operating member inresponse to shutter releasing operation; means following said movablemeans for actuating said switch to electrically isolate said means forstoring from said light measuring circuit with said movable means movingfrom said first position to said second position; said means forretaining said movable means and said following means actuating saidswitch prior to the releasing of said operating member; and means forrestraining said following means in the position for actuating saidswitch.
 7. A single lens reflex camera as in claim 6, wherein saidfollowing means is interconnected with said means for retaining to movetherewith, and said means for retaining is movable between a firstposition for retaining said operating member in said first positionthereof and a second position for allowing said operating member to moveto said second position and is interlocked with said movable means tomove therewith when the latter moves from the first position to thesecond position thereof, and further comprising means for restrainingsaid means for retaining in said second position thereof with saidoperating member in said second position thereof, and means fordisconnecting said means for retaining from said following means so thatsaid means for retaining may return regardless of said movable meanswhen said operating member returns from said second position thereof. 8.A single lens reflex camera as in claim 6, further comprising means forpreventing said movable means from returning to said first positionthereof when said operating member is in said first position thereof. 9.A single lens reflex camera as in claim 8, wherein said means forretaining retains said operating member in their respective firstpositions and vice versa in their respective second positions, and theoperating member includes said means for disconnecting said means forretaining from said following means.
 10. In a single lens reflex cameraoperable in a viewing condition and a photographing condition andcomprising a light measuring circuit having a light receptive elementfor receiving light from an object to be photographed through anobjective lens and for generating an output voltage representative ofthe object light intensity, means for storing said output voltage, andmeans for timing the closing of a shutter in accordance with said storedvoltage, and a switch mechanism including a switch for selectivelyconnecting said means for storing and said light measuring circuit,comprising: an operating member movable between a first position and asecond position respectively representing said viewing condition andsaid photographing position; means movable between a first position forretaining said operating member in said first position and a secondposition for allowing said operating member to move to said secondposition; means responsive to shutter releasing operation to bring saidmovable means from said first to said second position thereof to releasethe retainment of said operating member; means for restraining saidmovable means in said second position thereof with said operating memberin said second position thereof; means for releasing said means forrestraining with said operating member returning from said secondposition; means for disconnecting said movable means from saidresponsive means so that said movable means may return regardless ofsaid responsive means when said operating member returns from saidsecond position thereof; and means for actuating said switch toelectrically isolate said means for storing from said light measuringcircuit with said movable means moving from said first position to saidsecond position, said movable means and said means for actuatingoperating said switch prior to the releasing of said operating member.11. A single lens reflex camera as in claim 10, wherein said means foractuating said switch is a member interlocked with said movable means tomove therewith.
 12. A single lens reflex camera as in claim 11, whereinsaid movable means retains said operating member in their respectivefirst positions and vice versa in their respective second positions, andsaid operating member includes said means for disconnecting said movablemeans from said responsive means.